<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    div{
      width: 249px;
      height: 35px;
      border: 1px solid #000;
      position: relative;
    }
    div::after{
      content: '';
      position: absolute;
      top: 7px;
      right: 10px;
      width: 10px;
      height: 10px;
      border-right:1px solid hsl(180deg, 50%, 30%);
      border-bottom: 1px solid hsl(180deg, 50%, 30%);
      transform: rotate(45deg);
      transition: all .2s;
    }
    div:hover::after{
      transform: rotate(225deg);
    }
  </style>
</head>
<body>
  <div></div>
</body>
</html>